1. Field of Invention
This invention generally relates to the field of abrasive cleaners and in particular to compositions that utilize cullet as an abrasive.
2. Description of the Related Art
Abrasive cleaners are used everyday in both industrial and residential applications. Powdered abrasive cleaners have long been known to be useful for scouring hard metallic materials, pots and pans, porcelain sinks, fixtures, and other hard surfaces that require high levels of mechanical abrasive for effective cleaning. Moreover, abrasives are commonly incorporated into health and beauty aids to clean or exfoliate xe2x80x9csoftxe2x80x9d surfaces, such as skin.
A wide variety of abrasive cleaner formulations exist, including powders, pastes, standard liquids, and thickened liquids or gel compositions. The typical abrasive cleaner contains, in addition to abrasive particles, surfactants, fillers, and a preservative. Optionally, cleaners may also contain, for example, bleaching agents, fragrances, deodorizing agents, and color additives. The abrasive materials most commonly employed in cleaner compositions are calcium carbonate, sodium carbonate, and water-insoluble siliceous materials, such as crystalline silica (including sand, feldspar, pumice, volcanic ash, diatomaceous earth, bentonite, talc and the like). Also useful as abrasives are ground nutshells, hardwood sawdust, synthetic abrasives, and mixtures thereof.
In general, the use of silica, feldspar, limestone or calcite (calcium carbonate) of various degrees of fineness has been preferred because of their hardness and the fact that they result in a white product. Nonetheless, the size, hardness, and shape of the particles may vary depending upon the particular scouring application.
Of those abrasives that have come to be preferred, xe2x80x9csilica flourxe2x80x9d has found particularly widespread use. The term xe2x80x9csilica flourxe2x80x9d defines pulverized crystalline silica of about 45 microns (325 mesh) to about 75 microns (200 mesh) in size. After crystalline silica is mined, it is milled to a fine powder of the indicated size and packaged for shipment. The silica then is used industrially as an abrasive cleanser and as an inert filler in a variety of consumer products ranging from toothpaste to metal polish.
One problem with the widespread use of silica and calcium carbonate is that they are mined as raw products from limited, non-renewable resources. Although the mining of abrasives is currently economically feasible, costs will increase as these products become more scarce. In addition, the environmental damage done by some mining practices creates further problems.
A more immediate threat caused by the mining and milling of any material containing crystalline silica is that workers may be exposed to adverse health risks, such as the inhalation of silica dust particles, which can result in silicosis. Silicosis is a debilitating respiratory disease that leads to fibrosis, a condition marked by the abnormal increase in fiber-containing (scar) tissue in the lungs.
The other ingredients found in many scouring cleaners or cleansers may also pose health and environmental risks. For example, many household cleaners contain chlorine in chemical forms such as sodium hypochlorite. These substances are highly corrosive and can damage the eyes, skin, and mucous membranes. Moreover, inhalation of chlorine can irritate the lungs, which is particularly dangerous for people with heart or respiratory conditions.
In terms of environmental damage, chlorine discharge can combine with other compounds to form dioxins and organochlorines.
Research has linked exposure to these substances with birth defects, cancer, and other reproductive and developmental disorders.
Therefore, there is a need for abrasive cleaners that effectively clean surfaces with ingredients that are replenishable, inexpensive, widely available, and inert or less harmful to human health or the environment then has previously been known.
The invention meets the aforementioned need by providing an effective abrasive cleaner that contains cullet as the main abrasive ingredient. The invention stems from the discovery that compositions ranging from 10-100% by weight of broken glass (cullet) having a size of about 150 microns or less in diameter effectively cleans common surfaces. Preferably, 20%-100% by weight of the cleaning product is cullet, with the cullet particles ranging in size from about 63 microns (230 mesh) to about 45 microns (325 mesh) for powder formulations, and about 45 microns (325 mesh) to 38 microns (400 mesh) for liquid and paste formulations. The preferred size ranges of cullet particles have been found to provide an especially desirable level of cleaning and scouring with little or no scratching. However, cullet particle sizes above and below the preferred ranges have been found to be effective abrasives.
The term xe2x80x9cabrasivexe2x80x9d or xe2x80x9cabrasivesxe2x80x9d includes any substance, alone or in combination, used to abrade, scrape, or rub away another substance, such as during the act of cleaning or polishing a surface.
The term xe2x80x9cculletxe2x80x9d includes any type of broken refuse glass, such as, but not limited to, container glass (e.g. recyclable glass jars or bottles) of all colors, uncolored glass, plate glass (e.g. window panes), ceramic glass (e.g. coffee mugs), and mixtures thereof. For consistency throughout the specification, the use of the term xe2x80x9ccullet,xe2x80x9d shall refer to broken recyclable container glass (uncolored, colored, or mixed) unless indicated otherwise. However, this definition is not meant to limit the invention to cullet of a particular glass composition.
As used in this description, the terms xe2x80x9cmesh,xe2x80x9d xe2x80x9cmesh size,xe2x80x9d xe2x80x9cmesh valuexe2x80x9d or xe2x80x9cmesh sieve sizexe2x80x9d generally are defined as the number of openings per inch of a sieve or screen. Since increasing the number of openings per inch in a sieve requires that the openings become smaller, an inversely proportional relationship exists between mesh value and the size of the particles passing through a given screen. In practice, mesh values can indicate either a wide range of cullet particle sizes (i.e. a given size or less) that pass through a particular sieve or a precise range of particle sizes. For example, if a cullet sample is screened only with a 200 mesh sieve, the particles that pass through would be 75 microns in diameter or less (down to sub-micron sizes). If, however, the 200 mesh cullet sample subsequently is screened with a 220 mesh sieve, all 200 mesh particles that do not pass through the 220 mesh sieve will be approximately 72-75 microns diameter. In this manner, a given mesh number may indicate particles of one or a few precise sizes or may indicate a wide range of sizes below a certain maximum size. Unless otherwise indicated, all mesh values cited in this disclosure represent cullet particles that have been precisely sized.
Especially preferred powder formulations of the invention contain cullet that is about 53 microns (270 mesh) in size, while liquid and paste formulations contain cullet of about 38 microns (400 mesh) in size. Also preferably, the inventive cleaner compositions are formulated to include sugar-based surfactants, a preservative, one or more fillers (e.g. clays, gums). An important advantage of the preferred formulations of the invention is that they are designed to use cullet and other ingredients that are less harmful to human health or the environment than most ingredients used in common commercial abrasive cleaners.
An object of this invention is to provide a high-quality abrasive cleaner made with cullet that has performance characteristics that are comparable or better than existing cleaners.
A second object of this invention is to provide an effective abrasive cleaner that is made from a renewable resource instead of from virgin raw materials that must be mined.
A third object of this invention is to provide a scouring composition that effectively cleans hard surfaces while avoiding the use or discharge of substances that can be harmful to human health or to the environment.
A fourth object of the invention is to provide an effective abrasive cleaner that is inexpensively produced using commonly-available materials.
A fifth object is to provide an abrasive cleaner that promotes the use of post-consumer, recycled glass.
A sixth object of this invention is to provide a cullet- based scouring composition that effectively cleans hard surfaces with a minimum of xe2x80x9cscratchingxe2x80x9d damage to such surfaces.
A seventh object is to provide an abrasive cleaner including cullet that may be used to clean or abrade the skin.
The invention accomplishes these and other objects by providing novel and improved abrasive cleaners that include cullet.
Various other purposes and advantages of the invention will become clear from its description in the specification that follows and from the novel features particularly pointed out in the appended claims. Therefore, to the accomplishment of the objectives described above, this invention consists of the features hereinafter illustrated in the drawings, fully described in the detailed description of the preferred embodiments, and particularly pointed out in the claims. However, such drawings and description disclose only some of the various ways in which the invention may be practiced.